Run 6 EEMC Gain Calibrations - SMD


Goal: Use mips from pp minbias events to set absolute gains for EEMC towers, SMD strips, and all pre- and post-shower tiles for the 2006 run:
  1. analyze 1.8M pp minbias events from day 89 - runs 7089008, 7089013, 7089014, 7089015, 7089021, 7089022, 7089024, 7089025, 7089091, 7090008
  2. fit slopes of ungated SMD histograms: 3-4% statistical error in slopes -> sets strip-to-strip relative gains to ~6% accuracy
  3. mask out dead or "problem" strips
  4. for SMD 1st pass: estimate absolute SMD gains by global matching to last year -> need ~10% increase in conversion factor from 2005 Cu-Cu to 2006 pp minbias
  5. identify mips event-by-event via 000xx000 or 000x000 hit signature in both planes -> "mip ID"
  6. fit Gaussian (Landau) function to towers (pre/post tiles) gated by mip ID, use known geometry / energy loss to set absolute gains
  7. for SMD 2nd pass: sum ranges of consecutive SMD strips gated by mip ID to set absolute gains, check for eta dependence, compare to 2005 results
  8. other improvements?

Results: 1st pass SMD - relative gains

Most strip spectra are very clean. Typical spectrum is shown below:


Pedestal, single photoelectron peak are clearly visible. Determination of slope should be fairly insensitive to choice of fitting range -> channels 40-140 used here.

Complete sets of fitted spectra (pdf) can be viewed from table below

Sector 1U Sector 1V
Sector 2U Sector 2V
Sector 3U Sector 3V
Sector 4U Sector 4V
Sector 5U Sector 5V
Sector 6U Sector 6V
Sector 7U Sector 7V
Sector 8U Sector 8V
Sector 9U Sector 9V
Sector 10U Sector 10V
Sector 11U Sector 11V
Sector 12U Sector 12V


Tables of individual strip gains and errors (i.e., database entries)

Sector 1U Sector 1V
Sector 2U Sector 2V
Sector 3U Sector 3V
Sector 4U Sector 4V
Sector 5U Sector 5V
Sector 6U Sector 6V
Sector 7U Sector 7V
Sector 8U Sector 8V
Sector 9U Sector 9V
Sector 10U Sector 10V
Sector 11U Sector 11V
Sector 12U Sector 12V

 


Check all of above plots, search gain tables for anomalies.

Only 10 strips completely dead out of ~7000, beyond 40 'known' unconnected strips. Using 1st-pass gains, no masking, most sectors look very good in terms of uniformity:




File used to flag masked channels can be viewed here


Results: 1st pass SMD - absolute gains

By comparing to last year's final SMD results, after absolute gains had been set using the technique described on Jan's web page (see items 11 and 12), there is a systematic difference of about 10% in the slopes obtained. Given that the 2005 results used Cu-Cu minbias, while in 2006 we are using pp minbias, this is not unreasonable. To account for this, we have increased the ADC energy conversion factor by 10%, until final absolute gains for 2006 are completed.

For now:  strip-to-strip gains should be matched to 5-6%, absolute gains for each strip should be good to better than +/- 10%.

Comparison of database gains for 2006 to those for 2005, for two typical planes:






Actual 2006 gains for plane 05U (to show range / strip-to-strip variations)